Milwaukee County fire crews were called to the airport at about 9:30 a.m. after a Delta commercial plane began having engine trouble, authorities said. An airport public relations official told 12 News the mechanical trouble happened prior to take-off.

The assistant fire chief said there were no flames showing on the plane when they arrived. He said crews made sure the engine was not hot and then escorted the plane back to the gate where passengers were allowed back inside the airport.

A Delta representative said the passengers were booked onto other flights after their morning flight was canceled.